My friend Frank from Voxel Factory just printed it for me and it fits perfectly on my Nexus 4. The hole for the usb plug is however slightly too tight on the sides so I had to grind it with a nail file. The screen-side part could also be thicker in order to provide a better protection if the phone falls on the screen side. Other than that, I think the model is perfect.

I used different measuring instruments on my Nexus 4 to get the accurate numbers, so I could create a model in AutoCAD. Then I proceeded to use this model as basis for the cover. I will upload the Nexus 4 3D model within the next few days.